Fresnel integrals

MEX file to compute Fresnel integrals.

[C, S] = fcs(x) returns Fresnel integrals C ans S for argument x, x must be double and real.

F = fcs(x) returns complex F = C+i*S

Algorithm:
This function uses an improved method for computing Fresnel integrals with an error of less then 1x10^-9, described in:

Klaus D. Mielenz, Computation of Fresnel Integrals. II
J. Res. Natl. Inst. Stand. Technol. 105, 589 (2000), pp 589-590

Notes for Linux implementation
Compile this with:
mex -O fcs.c

Notes for Windows implementation
Compile this with:
mex -O fcs.c -DWIN32